The present invention relates to counter mechanisms and more particularly concerns an improved and simplified counter mechanism that is more readily and inexpensively fabricated.
As counter mechanisms find wider and ever-increasing use, it is of greater importance to simpify the manufacture and to improve reliability and ease of assembly. Common types of resettable counter mechanisms such as those shown in the patent to Howard, U.S. Pat. No. 3,529,769, the patent to Lapointe, U.S. Pat. No. 3,588,476 and the patent to Zielke, U.S. Pat. No. 3,597,595, which are typical of counters of this general type, employ a plurality of number wheels having transfer pinions that transmit an incremental motion to one wheel in response to a complete revolution of another wheel. A resetting mechanism, in the form of a number of bellcrank levers, cooperates with heart-shaped cams on the number wheels to reset all of these simultaneously. The resetting operation also moves the transfer pinions out of engagement with the number wheels and at the same time indexes or resets the transfer pinions. The pinions are indexed by forcing them against resilient spring fingers that are attached to the counter housing.
Relative axial positioning of the number wheels and transfer pinions may be achieved either by locating all of these with regard to the reset mechanism, as in Howard, by mounting partitions on the shafts, as in Lapointe, or by dividing the housing into independent chambers, as in Zielke.
A particular disadvantage of prior art constructions is the complexity and cost of manufacture and assembly. The requirement of fabricating and assembling separate plural element spring fingers for indexing transfer pinions adds both to cost and time of assembly. The need for great rigidity and dimensional stability of the housing of the device dictates the use in prior arrangements of a rigid metal housing that is often more costly and difficult to fabricate. The provision of separate chambers for each of the transfer pinions and number wheels provides for an unnecessarily complex housing and adds to the difficulty of assembly.
Accordingly it is an object of the present invention to provide a resettable counter mechanism that is inexpensive to manufacture, reliable in operation and eliminates or minimizes above-mentioned problems.